S197 Are Torsen Diffs worth it

[Tim.ocon]

Going to be putting some 3.55s in my 2014 V6 in the near ish future and wondering upgrading to a Torsen diff would be worth the money. I figured since I’ll be in there taking it all apart that would be the time to swap it.

What are the pros and cons and will I actually notice a difference

I’d most likely be buying the boss 302 Torsen

 

[TA28]

I have 2 t2r in rears for my fr500c. I like them on the track. 1 thing that's a disadvantage is if it breaks its not rebuildable. I spoke with torsen they sell no parts to repair it.
I just built a 8.8 with Detroit locker 4.30 gears. The locker is fully rebuildable and cheaper.
I also have 13 boss 302 LS . If you do burn outs on the street your going to blow the t2 up! But it does work well once mowing. Chris

 

[JDee]

IMHO, Torsen is better than a clutch pack diff, but they are not perfect nor indestructible. There's also a thing about an unloaded wheel can't transfer any torque. When it wears out (and it will wear out) you have to buy an entire diff, as far as I know that's the only way they come based on my experience when my diff took a dump.

They run hot on track so a cooler is essential. I found this out the hard way. If you're going to track the car plan on putting a cooler on right from the start. There's a couple of companies that make a diff cooler kit and that is money well spent. You can source the parts yourself, it's not complicated, but the kit makes it easier.

Everyone has their own secret sauce fluid as well, and in my experience none of them will protect a Torsen from failure if it doesn't have a cooler on it.

 

[Tim.ocon]

I have 2 t2r in rears for my fr500c. I like them on the track. 1 thing that's a disadvantage is if it breaks its not rebuildable. I spoke with torsen they sell no parts to repair it.
I just built a 8.8 with Detroit locker 4.30 gears. The locker is fully rebuildable and cheaper.
I also have 13 boss 302 LS . If you do burn outs on the street your going to blow the t2 up! But it does work well once mowing. Chris

Sounds like they are much more money and aren’t that much better.

Maybe someday I’ll invest in one but currently the car is still pretty tame

 

[Tim.ocon]

IMHO, Torsen is better than a clutch pack diff, but they are not perfect nor indestructible. There's also a thing about an unloaded wheel can't transfer any torque. When it wears out (and it will wear out) you have to buy an entire diff, as far as I know that's the only way they come based on my experience when my diff took a dump.

They run hot on track so a cooler is essential. I found this out the hard way. If you're going to track the car plan on putting a cooler on right from the start. There's a couple of companies that make a diff cooler kit and that is money well spent. You can source the parts yourself, it's not complicated, but the kit makes it easier.

Everyone has their own secret sauce fluid as well, and in my experience none of them will protect a Torsen from failure if it doesn't have a cooler on it.

I’ve looked into getting a diff cooler with the regular clutch LSD as mine was getting pretty hot and venting

I think the Torsen isn’t necessary at the moment. If my diff goes in the future I may grab one

 

[67GTA]

You won’t need a cooler on your stick axle - they hold more fluid and the movement of the fluid in and out of the center section allows them to stay cooler than the IRS cars. You do need a better vent solution than the stock breather - all of that fluid needs a place to expand to when hot, so an effective expansion tank is necessary for track duty.

For me, the Torsen completely transformed the cars ability to use on-throttle steering in long sweeper corners. Gentle throttle application as you progress though the turn actually turns the car without adding steering input. I believe this is more pronounced on the stick-axle cars vs. IRS as well. Overall, the Torsen is more predictable than the trac-loc diffs, which will change from lap to lap with heat and as they wear.

 

[Tim.ocon]

You won’t need a cooler on your stick axle - they hold more fluid and the movement of the fluid in and out of the center section allows them to stay cooler than the IRS cars. You do need a better vent solution than the stock breather - all of that fluid needs a place to expand to when hot, so an effective expansion tank is necessary for track duty.

For me, the Torsen completely transformed the cars ability to use on-throttle steering in long sweeper corners. Gentle throttle application as you progress though the turn actually turns the car without adding steering input. I believe this is more pronounced on the stick-axle cars vs. IRS as well. Overall, the Torsen is more predictable than the trac-loc diffs, which will change from lap to lap with heat and as they wear.

Hmmm
So maybe it is worth it. Have you had any issues with yours after installing it?
And how hard is the install compared to the regular clutch diff

 

[302BOB]

I bought my Boss without the torsen option......the cheapskate in me still lives on............I never raced my Boss so I don't think I need it...I quess I'll never know???????????

 

[67GTA]

Hmmm
So maybe it is worth it. Have you had any issues with yours after installing it?
And how hard is the install compared to the regular clutch diff

Set it and forget it - haven’t touched it since install in Feb 2021, other than fluid changes. (45+ track days/TT competitions) Install is exactly the same with either diff type.

 

[Tim.ocon]

Set it and forget it - haven’t touched it since install in Feb 2021, other than fluid changes. (45+ track days/TT competitions) Install is exactly the same with either diff type.

Sounds like a pretty good deal then. Do you run a diff cooler?

 

[blacksheep-1]

Every racecar Phoenix built had a Torsen in it. So, I would say they are worth it just based on that. Yes they also had diff/ trans/ engine oil coolers but they were making 450 and up HP, your V6 should be fine with one.
Also, if you choose to do the install yourself, there are several threads on here.

 

[Mad Hatter]

Torsen all the way! When you see a pack (herd?) of Mustangs at the track, the fast ones have a torsen, the rest do not. As 67GTA says, its the fast corners that really show the torsen off.

 

[67GTA]

Sounds like a pretty good deal then. Do you run a diff cooler?

I do not. I will add one for 30+ min sprint races or enduros if I eventually go WTW, but not worth the weight penalty now for competitive time trial.

 

[Mad Hatter]

With the stick axle we ran a 3 hour enduro and we had no rear axle heat problems. We won! So I guess the car was being pushed pretty hard. Would not do that with a S55 though. The drivers were pretty hot though . funny, after a 45 min stretch, I was very very motion sick.. Almost made a mess inside the car.

 

[RodS197]

+1 on the torsen. I wouldn’t run without it. Helps the car turn. Get a good axle vent, Bobs is the best if you have an interior. I don’t, so mine vents inside the car. I’ve never needed a cooler on my S197. Huge heat sink back there that looks like an axle!

 

[TeeLew]

The Torsen is a better diff than the stock Traction-Lock, but it's not a slam-dunk.

Trac-Lok has about a 2:1 bias ratio
Trac-Lok degrades very quickly. It can only take a certain number of 'traction events' (single wheel wheelspin) before the wear faces degrade and it starts peg-legging.
Preload goes away with the clutch wear faces.
----------------------------------------------------------------------
The Torsen doesn't have much preload and no option to add it.
The Torsen never really locks up. It's always trying to differentiate, which means they tend to create excess heat. Plates are more of a stick-or-slip proposition. Once they lock, they are pretty much locked.
A Torsen is about 10# heavier than a Trac-Lok.

I was painted into a corner to run a Trac-Lok by my gear choice (Super 8.8 w/ 3.15, S550). I made a different clutch pack for the stock diff with steel plates, like a race diff. The stock is stamped steel with phenolic pucks and they are not very flat. Mine are ground/hardened tool steel. They are very flat and make much better plate-to-plate contact which alone gives a good gain in torque bias. It uses 5 drive/driven plates on each side (stock is 3), so there's a 60% increase in torque bias in that. With the additional plates and shimming it tight gives 150 ft.lb. preload on the diff. I think I can get more, but I can definitely get less. There isn't much to wear on these, so I don't see it changing much once it's run in.

It's noisy in a parking lot, but it works.


BTW, I spent way too much doing this.

 

[blacksheep-1]

The Torsen is a better diff than the stock Traction-Lock, but it's not a slam-dunk.

Trac-Lok has about a 2:1 bias ratio
Trac-Lok degrades very quickly. It can only take a certain number of 'traction events' (single wheel wheelspin) before the wear faces degrade and it starts peg-legging.
Preload goes away with the clutch wear faces.
----------------------------------------------------------------------
The Torsen doesn't have much preload and no option to add it.
The Torsen never really locks up. It's always trying to differentiate, which means they tend to create excess heat. Plates are more of a stick-or-slip proposition. Once they lock, they are pretty much locked.
A Torsen is about 10# heavier than a Trac-Lok.

I was painted into a corner to run a Trac-Lok by my gear choice (Super 8.8 w/ 3.15, S550). I made a different clutch pack for the stock diff with steel plates, like a race diff. The stock is stamped steel with phenolic pucks and they are not very flat. Mine are ground/hardened tool steel. They are very flat and make much better plate-to-plate contact which alone gives a good gain in torque bias. It uses 5 drive/driven plates on each side (stock is 3), so there's a 60% increase in torque bias in that. With the additional plates and shimming it tight gives 150 ft.lb. preload on the diff. I think I can get more, but I can definitely get less. There isn't much to wear on these, so I don't see it changing much once it's run in.

It's noisy in a parking lot, but it works.


BTW, I spent way too much doing this.

I'm a Torsen guy, but TeeLew's clutch packs transform the Ford 8.8 limited slip unit. I have one in Superbeater and wish I had them in my F150.

 

[Alex_murrica]

The Torsen is a better diff than the stock Traction-Lock, but it's not a slam-dunk.

Trac-Lok has about a 2:1 bias ratio
Trac-Lok degrades very quickly. It can only take a certain number of 'traction events' (single wheel wheelspin) before the wear faces degrade and it starts peg-legging.
Preload goes away with the clutch wear faces.
----------------------------------------------------------------------
The Torsen doesn't have much preload and no option to add it.
The Torsen never really locks up. It's always trying to differentiate, which means they tend to create excess heat. Plates are more of a stick-or-slip proposition. Once they lock, they are pretty much locked.
A Torsen is about 10# heavier than a Trac-Lok.

I was painted into a corner to run a Trac-Lok by my gear choice (Super 8.8 w/ 3.15, S550). I made a different clutch pack for the stock diff with steel plates, like a race diff. The stock is stamped steel with phenolic pucks and they are not very flat. Mine are ground/hardened tool steel. They are very flat and make much better plate-to-plate contact which alone gives a good gain in torque bias. It uses 5 drive/driven plates on each side (stock is 3), so there's a 60% increase in torque bias in that. With the additional plates and shimming it tight gives 150 ft.lb. preload on the diff. I think I can get more, but I can definitely get less. There isn't much to wear on these, so I don't see it changing much once it's run in.

It's noisy in a parking lot, but it works.


BTW, I spent way too much doing this.

Where can I get a @TeeLew special clutch pack? I’m ready to pull the trigger on a diff upgrade and this sounds like a great option.

 

[blacksheep-1]

Where can I get a @TeeLew special clutch pack? I’m ready to pull the trigger on a diff upgrade and this sounds like a great option.

It's less expensive, greatly improved the 8.8, but IMO is not as good as the Torsen for all out performance.
Ask @TeeLew

 

[TeeLew]

It's less expensive, greatly improved the 8.8, but IMO is not as good as the Torsen for all out performance.
Ask @TeeLew

I think this is a pretty fair review. Blacksheep is running the 4x4 version and I'm running 5x5. The Torsen does a really good job of allowing the car to turn on-throttle. As you go to throttle, the plate diff will slip, slip, lock. It's just not quite as smooth as the Torsen. The 4:1 bias ratio Torsen is definitely the Easy Button. You can't really go wrong with that choice, IMO.

I do think the ability to add preload is important to improve braking. Even with a Torsen you can get inside rear wheel locking in a bumpy brake zone. The OS Giken has all the tools available. It's a plate diff, but activated by ramps instead of just the side gears. This allows you to have different bias ratios on coast and drive. The preload is shim adjustable. There are some other tuning tools on it, too, but they're a little more tricky to use. I think they only make the S550 version, but if there's a 197 option, it's worth a look.

I've thought about making a run of my plates to sell, but they're not cheap. The material really drives the cost up, but I made the choice based off recommendations from some guys who know their stuff. I can use cold-rolled 4130 and I think it would do the same job for a lot less. I haven't added it all up, but I'm probably close to $1k for a set of plates. It's a hell of a lot easier job than changing the entire differential, but it's not really all that less expensive.